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Balance problem with gimbal


flemming laybourn
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Hello fellow operators..!

 

I have what might be a silly question ( considering that I have been operating for quite a while now...) But here goes:

 

When I line up my rig and do the balance and droptime, something funny happens..

If everything is super duper...and I swing the rig 180' ( camera pointing in opposite direction ) 50% of the time my rig goes off level....hmmm.. I spoke with Howard at MK-V

who responded that It might just be a question of "trimming" the different components ( monitor, batteries..ect..) in relation to each other... and I have tried that, and sometimes it workes..and sometimes not..

Im ofcourse worried that something is not right with my gimbal, since paning the camera ( in my opinion) shouldn´t screw up the level.....

 

Any comments / experiences would be much apriciated...

 

All the best

 

Flemming Laybourn

Denmark

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Hi Flemming.

 

I had a similar problem a few weeks ago with my Master gimbal.

I found out that the alignment in the fork bearings was not correct and this caused the off-balance.

This is "easily" corrected on the Master gimbal, I don´t know what kind you have.

 

In my case it turned out to be the adjustible axes in the forkbearings that were not locked anymore by their little Allen bolts. So everytime I tilted or turned, they would work themself in some direction (there is always a little bit of friction, specially fully loaded) and would make more play in one way.

 

Try to move the gimble sideways. If this is possible (without load) you have to get rid of the play.

Then, you have to center it as well, as you can remove the play but still be off-center.

 

It´s a bit of trial and error procedure,but I got rid of my problem!

 

Rob van Gelder, Bangkok, Thailand

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Guest SebastianMatthias

hello flemming (is that your name ????)

yes,it probably is your gimbal.i just had that problem yesterday and marcus (baerbel) fixed it for me.it somehow has to do with the axis of your gimbal-joke

(the handle) in relation to the center-axis of your post.in the best case it has to cross that axis all the time.if it lays just a tiny bit beside it ,it won´t hit the middle of that axis when you turn the rig 180° even if it is perfectly balanced.i don´t know what rig you have so i just can talk about the baerbel.on the gimbal are a few tiny screws wich change the distance from the gimbal to the post.so if you spin the gimbal you should see the movement of the outer ring.(mine was doing a real 8 yesterday!!!)

i´m pretty sure that this might be your problem,but there are probably more operators and craftsmen out there who know more details about it than i do.

 

by the way: thank you baerbel for your excellent service and your shoulder to cry on every time i do something stupid to my rig!!!!!

 

 

hope i could help you

 

 

cheers

 

sebastian "kepps spinning" matthias :ph34r:

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Flemming,

 

When you say that your rig goes off level; how many inches (or cm) does the bottom of the post wander out from vertical and is it side to side or fore/aft? What drop time are you balancing with? Fast drop times will tend to hide the problem and slow drop times have the opposite effect.

 

Because this fault is happening only half of the time, it's more likely to be some slight play somewhere in the gimbal, rather than misalignment of the bearings. Check for any looseness.

 

Paul

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Hi flemming,

 

I had exactly the same problem. I've got a Master Sled & Gimbal and started noticing way to much play between the gimbal yolk and gimbal. If you have a Master Gimbal then speak to the tech guys at Tiffen, they'll email you a step by step guide to Re-Centering the unit. I did it and have to say it was a bugger, lot's of trial error but be patient you will get it eventually.

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Thanks everyone for the great feedback... ( and yes..Flemming is my name.. :) )

 

I have an Mk-V rig, and have experienced the same "situations" with 2 gimbals.

Tomorrow will be "the big gimbal day", And I will probably put out a "the Gimbal...and how to spin it"- DVD when Im finished.... ( maybe with Cindy Crawford as the host..hmm)

 

But again thanks for taking your time to reply..!

 

All the Best

 

Flemming "yes thats my name" Laybourn

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I have an Mk-V rig, and have experienced the same "situations" with 2 gimbals.

Fleming,

 

Are both of the gimbals that you've had a problem with from the same manufacturer?

Do let us know how it goes tommorrow: im sure there are others on this forum who would think twice about purchasing that gimbal if this is to be a common problem with it.

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Hi,

 

Bear in mind that a certain amount of wonkiness in this respect is unavoidable and normal. There's an enormous amount of length and leverage around the gimbal and even minuscule, tenths-of-a-thou errors will produce this effect. I guess it depends on how much more your particular outfit does it now than when it was new.

 

Phil

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Hi guys,

 

Flemming isn't your gimbal basically brand new? i seem to remember you mentioning a while ago that you had just recieved it!

 

I have had that kind of trouble with older Efp-gimbals and is usually a case of the gimbals being worn out...earings,play etc. like some of you said.It seems a bit scary that a pretty new gimbal would have the same symptoms...

 

 

Sebastian Jewell.

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Hello Flemming,

 

The problem is just as explained by Mattias. The center of the post/pan bearing is not lined up with the center line axes of the gimbal yoke (Tilt & Yaw).

 

This issue will become more pronounced with slower drop times as increased bottom weight masks the problem.

 

Aligning for this issue is a great concern in production. Often a system would not ship if the rig did not pass this "180 degree" pan test at a four second drop time.

 

It is amazing the issues that are learned over the years. In the early 80's operators were using rigs that did not dynamically balance and had no clue of these nuances that were affecting the equipment. Now think of some of your most favorite "classic" shots and doing them with a model I or II that didn't pan flat. Now that's talent.

 

You kids are spoiled.!.!.! :D

 

James

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Folks--

 

What you have here is a classic case of bearings not sitting true inside your Gimbal.

 

The only way to correct this malady is to shim the bearings back into a true state of flattness.

 

This process is critical down to one-half thousandth of an inch.

 

Needless to say, this operation requires a surface plate and dial indicators and steady hands.

 

Been at this Gimbal game for a bunch of years now, so if you need help, drop me a line.

 

Best,

 

Brant S. Fagan, SOC

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